KR100619046B1 - Fusing roller and fusing apparatus using the same - Google Patents

Abstract

A fixing roller and a fixing apparatus using the same are disclosed. The disclosed fixing roller includes an induction coil part for generating alternating magnetic flux that changes in correspondence with a predetermined alternating current, a heating roller part for generating heat by an induction current generated by the alternating magnetic flux, and located outside the heating roller part. And an offset portion for canceling the induced current generated by the alternating magnetic flux at a predetermined portion of the heating roller portion.

Description

Fusing roller and fusing apparatus using the same

1 is a cross-sectional view showing a fixing device using a conventional halogen lamp as a heat source,

2 is a longitudinal cross-sectional view taken along the line II ′ of FIG. 1;

3 is a cross-sectional view showing the configuration of a fixing device to which a fixing roller according to a first embodiment of the present invention is applied;

4 is a configuration diagram showing a power supply unit of a fixing roller according to the present invention;

5 is a schematic diagram for explaining an operation in which the induced current generated in the heating roller unit is canceled by the offset unit in the fixing device according to the present invention;

Figure 6 is a diagram schematically showing a heating source for generating heat in the fixing roller according to the present invention,

7 is a cross-sectional view showing the configuration of a fixing roller according to a second embodiment of the present invention;

8 is a cross-sectional view showing the configuration of a fixing roller according to a third embodiment of the present invention;

9 is a cross-sectional view showing the configuration of a fixing roller according to a fourth embodiment of the present invention.

<Description of the symbols for the main parts of the drawings>

110 ... Fixing Roller 111 ... Coating Layer

112 Heat roller section 113 Insulation layer

114.Induction coil part 115 ... Adhesive

116 ... lead part 117 ... internal space

120 End cap 121 Power end cap

122 Pore 123 Electrode

130,230,330,430 ... Offset 131,231,331,431 ... bobbin

132,232,332,432 ... Coil 140 ... Pressure Roller

The present invention relates to a fixing apparatus, and more particularly, to a fixing apparatus having a fixing roller capable of applying heat only to a recording medium by adjusting a heating portion corresponding to a narrow recording medium.

In general, an electrophotographic image forming apparatus such as a laser printer and a digital copying machine scans light onto a photosensitive medium charged at a constant electric potential to form an electrostatic latent image, and uses a developing machine to produce an electrostatic latent image of a toner of a predetermined color. It is a device that prints monochrome image or color image by developing and transferring it to paper.

Such electrophotographic printing presses are roughly classified into wet and dry electrophotographic printing presses depending on the developer used. A wet electrophotographic printing press uses a developer in which powdery toner is dispersed in a liquid carrier. Dry electrophotographic printing presses use a two-component developer in which a powdered carrier and a toner are mixed or a one-component developer without a carrier. Hereinafter, a dry electrophotographic printer will be described. For convenience, a developer is referred to as a toner.

1 is a cross-sectional view showing a fixing device using a conventional halogen lamp as a heat source, Figure 2 is a longitudinal cross-sectional view taken along the line II 'shown in FIG.

The fixing device 10 is provided with two cylindrical fixing rollers 11 and 12 made of aluminum, both ends of which are supported by bearings 14 so as to face each other along the longitudinal direction. On the surface of the fixing rollers 11 and 12, a coating layer 13 is formed not only to form a nip (NIP) through which heat is transferred to the image but also to improve releasability with the image.

Inside the fixing rollers 11 and 12, there are provided heat generating units 15 each using a halogen lamp as a heat source that is connected to an external power source (not shown) to generate heat. The heat generating part 15 and the fixing rollers 11 and 12 are spaced apart from each other and filled with air therebetween.

When current supplied from an external power source (not shown) is applied to both ends of the heat generating unit 15, the heat generating unit 15 generates radiant energy. The generated radiant energy is transmitted to the inner wall of the fixing rollers 11 and 12 through air, and is converted into thermal energy in a light-heat conversion layer made of a black body to conduct the fixing rollers 11 and 12 and the coating layer 13 by conduction. It is transmitted to the image 21 on the recording medium 20 passing through the nip (NIP) that is the contact portion of the fixing roller (11, 12). Thus, the image 21 is melted by thermal energy and fused onto the recording medium 20.

A fixing device using a halogen lamp as a heat source as described above has the following problems.

First, since halogen lamps have low thermal efficiency, a significant warm-up time is required from the normal temperature to the fixing temperature when the power is supplied for printing. The user must wait until the fixing roller temperature reaches the fixing target temperature and becomes available for printing.

Second, since the halogen lamp and the fixing roller are spaced apart from each other and air is interposed therebetween, the heat generated from the halogen lamp heats the fixing roller by radiation and passes through the fixing roller by conduction. However, it is difficult to control the temperature spread because the temperature difference between the portion with and without the image is compensated for as the heat is transferred to the recording medium in contact with the recording medium.

Third, power consumption is high because the fixing roller must be maintained at a constant temperature by continuously supplying current to the heating part in order to allow the next printing job to be performed smoothly while the printing job is temporarily stopped.

Fourth, in the case of using a recording medium of various sizes, even if printing using a recording medium of a relatively small size, heat is generated even in a portion where the recording medium does not pass, so that the temperature of the portion increases and the deterioration of parts High probability of destruction.

The present invention has been made in view of the above problems, and by using resistance and induction heat as a heat generating source, it is possible to shorten the warm-up time by reaching a fast time to the fixing temperature and to adjust the heat generating area according to the size of the recording medium. It is an object of the present invention to provide a fixing apparatus of an image forming apparatus.

In order to achieve the above object, the fixing roller of the present invention includes an induction coil part for generating an alternating magnetic flux that changes in correspondence with a predetermined alternating current, a heating roller part for generating heat by an induction current generated by the alternating magnetic flux; Located on the outside of the heating roller portion, and provided with an offset portion for canceling the induced current generated by the alternating magnetic flux at a predetermined portion of the heating roller portion.

According to the present invention, the induction coil portion is wrapped with an insulating layer to generate an alternating magnetic flux that is changed by a predetermined alternating current, and is in close contact with the inner surface of the heating roller portion by an adhesive.

According to the present invention, the heating roller part is heated by heat by induction heating of the induced current generated by the heat of resistance and the alternating flux of the induction heating unit itself.

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According to the invention, the offset portion is located on the outside of the heating roller portion, it is located opposite the predetermined portions on both sides of the induction heating portion.

According to the invention, the offset portion is located on the outside of the heating roller portion, it is located opposite a predetermined portion of one side of the induction heating portion.

According to the present invention, the offset portion is fixed without rotating like the heating roller portion.

According to the invention, it further comprises a power supply for generating a predetermined high frequency AC current.

According to another feature of the invention, a fixing roller having a fixing roller for generating heat for fusing an image onto a recording medium and a pressing roller which is installed to face the fixing roller so as to contact the fixing roller and presses the recording medium toward the fixing roller. In the apparatus,

The fixing roller may include an induction coil part for generating an alternating magnetic flux that changes in correspondence with a predetermined alternating current, a heating roller part for generating heat by an induction current generated by the alternating magnetic flux, and an outer side of the heating roller part. And an offset portion for canceling the induced current generated by the alternating magnetic flux at a predetermined portion of the heating roller portion.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

Figure 3 is a cross-sectional view showing the configuration of the fixing device to which the fixing roller according to the first embodiment of the present invention, Figure 4 is a block diagram showing a power supply of the fixing roller according to the present invention, Figure 5 is a present invention Figure 6 is a schematic diagram for explaining the operation that the induced current generated in the heating roller in the fixing device according to the offset portion canceled, Figure 6 is a schematic diagram as a heat generating source for generating heat in the fixing roller according to the present invention to be.

3 and 4, the fixing device 100 is installed to be in contact with the fixing roller 110 which generates heat for fusion of the toner image to the recording medium and the fixing roller 110 in the longitudinal direction, so as to contact the contact portion ( And a pressure roller 140 for pressing the recording medium passing through the NIP toward the fixing roller 110.

The pressure roller 140 has a tubular body 141 is rotatably supported on the shaft 143, the coating layer 142 is formed on the outer circumferential surface of the body 141 to facilitate releasability with the toner image have. In some cases, a fixing roller may be used instead of the pressing roller to generate heat at the same time as pressing.

The fixing roller 110 is composed of a heating roller portion 112, the induction coil portion 114, the offset portion 130 and the power supply unit 150.

The heating roller part 112 is a hollow tubular member made of a resistor. The coating layer 111 is formed on the surface thereof to be coated with Teflon or the like to improve releasability with the toner image. The heating roller part 112 has a property of being magnetized by a magnetic field and having a conductor property capable of flowing a predetermined current, for example, an iron alloy, a copper alloy, an aluminum alloy, a nickel alloy, a chromium alloy, or the like. It is preferable to consist of the same material.

The induction coil part 114 is installed to be in close contact with the inner surface of the heating roller part 112 in a spiral to generate an alternating magnetic flux that changes in correspondence with the current input from the power supply unit 150. . It is preferable that the induction coil part 114 is made of a copper material ribcoin (ribbon) coil. The induction coil part 114 is wrapped with the insulating layer 113 and is in close contact with the inner surface of the heating roller part 112 using the heat resistant adhesive 115.

The insulation layer 113 insulates the insulation coil 113 from an insulation breakdown and does not cause leakage current when an AC current is input to the induction coil part 114. The insulating layer 113 should have a predetermined breakdown voltage characteristic and dielectric breakdown resistance. The breakdown voltage property indicates a property that can withstand a predetermined external power supply, and the breakdown resistance property is a property in which leakage current does not occur more than 10 mA and breakdown does not occur for 1 minute under the maximum breakdown voltage. The insulating layer 113 may be made of mica, polyimide, ceramic, silicon, polyurethane, glass, PTFE, or polytetrafluoruethylene.

Both ends of the induction coil unit 114 are connected to the lead unit 115 to conduct with the power supply unit 150, respectively.

When a predetermined AC current is input to the induction coil part 114, an alternating magnetic flux is generated in the induction coil part 114, and the alternating magnetic flux supplies a predetermined induction current (eddy current) to the heating roller part 112. Generate. At this time, since the heating roller 112 has its own intrinsic resistance, it generates resistance in accordance with the induced current.

The offset unit 130 is installed to face each of the predetermined portions on both sides of the induction heating unit 114 inside the heating roller unit 112 to generate an induction current corresponding to an alternating current input from the outside. The induction coil 114 cancels the induced current generated in the heating roller 112. Therefore, the heating roller portion 112 facing the offset portion 130 does not generate an induction current and does not generate resistance heat.

The offset portion 130 is preferably wound around the coil 132 on the outer circumferential surface of the cylindrical bobbin 131. The offset portion 130 is preferably rotated together with the heating roller portion 112. For convenience of description, the configuration in which the offset unit 130 is connected to an external power source is not illustrated.

The reason for installing the offset unit 130 as described above is to save energy when heating only the portion where the recording medium (not shown) passes when the image is formed on a small recording medium (not shown) such as an envelope. This is because it is possible to improve the durability of the fixing roller 110.

The end cap 120 and the power transmission end cap 121 are respectively installed at both ends of the heating roller part 112. The power transmission end cap 121 has a configuration similar to that of the end cap 120, but is connected to a transmission device (not shown) so that a power transmission means (not shown) such as a gear to rotate the fixing roller 110 is provided. It is prepared.

 The end cap 120 has an air vent 122 formed therein. The pore 122 is the end cap 120 is installed in the heating roller portion 112, the air inside the inner space 117 and the outside of the heating roller portion 112 through the inner space 117 Ensure that the pressure at is maintained at atmospheric pressure.

Therefore, even when the heating roller part 112 is heated by the heat transferred from the induction coil part 114, the internal space 117 passes outside air through the pores 122, so that atmospheric pressure is maintained. The pore 122 may be provided in the power transmission end cap 121. In addition, the pores 122 may be provided in both the end cap 120 and the power transmission end cap 121.

Electrodes 123 are installed on the end cap 120 and the power transmission end cap 121, respectively. The electrode 123 is electrically connected to the lead unit 115. The current input from the external power source is supplied to the induction coil part 114 via the power supply device 150 → electrode 123 → lead part 115.

As illustrated in FIG. 4, the power supply unit 150 includes a power supply unit 151, a line filter unit 152, a rectifier 153, and a high frequency current generator 154.

The power supply unit 151 provides an AC current having a predetermined size and frequency.

The line filter unit 152 includes an inductor L and a capacitor C. The line filter unit 152 receives an AC power from the power supply unit and removes a high frequency component included in the AC current. That is, the AC current provided from the power supply unit 151 is smoothed.

The rectifier 153 rectifies the AC current provided by the line filter unit 152 to generate a current of a DC component. The rectifier 153 is a bridge rectifier composed of four diodes D1, D2, D3, and D4, and rectifies an AC current into a DC component current according to the four diode polarities.

The high frequency current generator 154 receives a current of a DC component provided from the rectifier 153 and generates a high frequency AC current. The high frequency current generator 154 includes two capacitors C2 and C3 and two switches SW1 and SW2. The high frequency current generator 154 converts the DC current rectified by the rectifier 153 into a high frequency AC by opening and closing the switch. Convert it to current. The low frequency current generator may be used instead of the high frequency current generator 154. The power supply unit 150 is an example for describing the present invention, and various modifications may be applied.

An operation in which heat is generated in the fixing roller according to the first embodiment of the present invention configured as described above or heat is canceled by the offset unit will be described with reference to the drawings.

5 and 6, when an alternating current is input from the power supply unit 150 to the induction coil unit 114, the induction coil unit 114 has an alternating magnetic flux A shown by a solid line around the induction coil unit 114. Occurs. The alternating magnetic flux (A) generated in the induction coil portion 114 bridges the heating roller portion 112, and the heating by the change of the alternating magnetic flux (A) that chains the heating roller portion (112). In the roller part 112, induction currents B and C of different directions shown by solid lines are generated.

At this time, since the heating roller unit 112 has its own resistivity, the induction current (B) (C) is the Joule heat (hereinafter referred to as induction Joule heat, G) to the heating roller unit 112. Occurs. The induced streak G is conducted by the heating roller part 112 and transferred to the toner image via the protective layer 111.

In addition, since the induction coil part 112 also has its own resistance, resistance is generated by the input AC current, thereby generating Joule heat (hereinafter referred to as resistance Joule heat, H). The resistance string H is transferred to the toner image (not shown) through the heat insulation layer 113 → the adhesive 115 → the guide coil portion 112 → the protective layer 111.

Therefore, when an AC current is input to the induction coil part 114, the resistance string H generated from the induction coil part itself and the alternating magnetic flux A generated around the induction coil part 112. The toner image (not shown) transferred to the recording medium (not shown) is fused by the induced streak G by the induction currents B and C generated in the heating roller unit 112.

On the other hand, when the current flowing in the opposite direction to the current input to the induction coil unit 114 to the offset unit 130, the alternating magnetic flux (D) is opposite to the direction shown by the dotted line in Figure 5, Induced currents E and F are generated in the heating roller part 112 in different directions by the alternating magnetic flux D. The induction current (E) (F) is in a different direction from the induction current (B) (C) generated by the induction coil portion 114. Therefore, the induction current (B) and the induction current (E), the induction current (C) and the induction current (F) are canceled with each other, the induction to the heating roller portion 112 facing the offset portion 130 Joule heat (G) is not generated.

Therefore, as shown in FIG. 3, the portion L1 and L3 of the heating roller part 112 facing the offset portion 130 generate the resistance string H, but the induction string G. Since the heat roller 112 does not generate heat as much as the induction Joule heat G than the portion L2 that does not face the offset portion 130, the temperature becomes low.

7 is a cross-sectional view showing the configuration of a fixing roller according to a second embodiment of the present invention.

Referring to Figure 7, the fixing roller according to the second embodiment of the present invention is similar in configuration to the fixing roller according to the first embodiment of the present invention shown in Figure 3, only the offset portion 130 is a heating roller Inside the part 112, the induction heating part 114 is provided so as to face only a predetermined portion. Therefore, the portion of the heating roller portion 112 that faces the offset portion 130 does not generate induced streak G so that the temperature is lower than that of the portion that faces the offset portion 130. do.

8 is a cross-sectional view showing the configuration of a fixing device to which a fixing roller according to a third embodiment of the present invention is applied.

 Referring to Figure 8, the fixing roller according to the third embodiment of the present invention is similar in configuration to the fixing roller according to the first embodiment of the present invention shown in Figure 3, only the offset portion 130 is a heating roller The outer side of the part 112 is provided so as to oppose predetermined portions on both sides of the induction heating part 114, respectively. Therefore, the portion of the heating roller portion 112 that faces the offset portion 130 does not generate induced streak G so that the temperature is lower than that of the portion that faces the offset portion 130. do.

9 is a cross-sectional view showing the configuration of a fixing device to which a fixing roller according to a fourth embodiment of the present invention is applied.

Referring to Figure 9, the fixing roller according to the fourth embodiment of the present invention is similar in configuration to the fixing roller according to the first embodiment of the present invention shown in Figure 3, only the offset portion 430 is a heating roller The outer side of the part 112 is provided so that it may oppose only one predetermined part. Therefore, the heating roller part 112 maintains a lower temperature than the part facing the offset part 430 because the part facing the offset part 430 does not generate induced joule heat.

As described above, the fixing roller according to the present invention and the fixing apparatus to which the fixing roller is applied have the following effects.

First, by providing an offset portion inside the fixing roller, it is possible to prevent excessive temperature rise by canceling the induced current in the portion that does not contact the narrow recording medium.

Second, the induction coil portion using a high insulating material, by using a high temperature adhesive to be in close contact with the inside of the heating roller portion can increase the thermal efficiency,

Third, there is an effect that the warm-up time to the fixing target temperature can be shortened by heating the heating roller part by using the resistance heating and the induction heating by the induction coil part together.

Although the present invention has been described with reference to one embodiment shown in the drawings, this is merely exemplary and will be understood by those of ordinary skill in the art that various modifications and variations can be made therefrom. Therefore, the true technical protection scope of the present invention will be defined by the technical spirit of the appended claims.

Claims (20)

An induction coil part for generating an alternating magnetic flux that changes in correspondence with a predetermined alternating current input; A heating roller unit that generates heat by an induced current generated by the alternating magnetic flux; And an offset part positioned outside the heating roller part to offset the induced current generated by the alternating magnetic flux at a predetermined portion of the heating roller part. The method of claim 1, The induction coil part The fixing roller is wrapped with an insulating layer, and generates alternating magnetic flux that changes according to a predetermined alternating current, and is fixed to the inner surface of the heating roller by adhesive. The method of claim 1, The heating roller part A fixing roller, characterized in that heated by the heat generated by the resistance heating of the induction heating unit itself and the heat generated by the induced heating of the induced current generated by the alternating magnetic flux. delete delete delete The method of claim 1, The offset portion A fixing roller, characterized in that it is located opposite the predetermined portions on both sides of the induction heating portion. The method of claim 1, The offset portion A fixing roller, characterized in that the position facing the predetermined portion on one side of the induction heating portion. The method according to claim 7 or 8, The offset portion A fixing roller which is fixed without being rotated like the heating roller part. The method of claim 1, A fixing roller further comprising a power supply for generating a predetermined high frequency alternating current. A fixing apparatus comprising a fixing roller which generates heat for fusion bonding an image onto a recording medium, and a pressing roller which is installed to face the fixing roller so as to contact the fixing roller, and presses the recording medium toward the fixing roller. The fixing roller is An induction coil part for generating an alternating magnetic flux that changes in correspondence with a predetermined alternating current input; A heating roller unit that generates heat by an induced current generated by the alternating magnetic flux; And an offset portion positioned outside the heating roller portion to offset an induced current generated by the alternating magnetic flux at a predetermined portion of the heating roller portion. The method of claim 1, The induction coil part A fixing device wrapped with an insulating layer, generating alternating magnetic flux that is changed by a predetermined alternating current, and being in close contact with an inner surface of the heating roller unit by an adhesive. The method of claim 11, The heating roller part A fixing device characterized in that heated by the heat generated by the resistance heating of the induction heating unit itself and the heat generated by the induced heating of the induced current generated by the alternating magnetic flux. delete delete delete The method of claim 11, The offset portion A fixing device, characterized in that it is located opposite the predetermined portions on both sides of the induction heating unit. The method of claim 11, The offset portion A fixing device, characterized in that it is located opposite the predetermined portion of one side of the induction heating unit. The method of claim 17 or 18, The offset portion A fixing device, which is fixed without rotating like the heating roller part. The method of claim 11, A fixing device further comprising a power supply for generating a predetermined high frequency alternating current.

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